Hilo

Today: Mostly sunny with isolated showers. Highs around 78 near the shore to 63 to 69 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 67 near the shore to around 52 at 4000 feet. Northwest winds around 10 mph. Chance of rain 50 percent.

Wednesday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 79 near the shore to around 66 at 4000 feet. Northwest winds around 10 mph shifting to the northeast in the afternoon. Chance of rain 40 percent.

Kona

Today: Mostly sunny. Isolated showers in the afternoon. Highs around 81 near the shore to around 67 near 5000 feet. Light winds. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 65 to 70 near the shore to 47 to 52 near 5000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 81 near the shore to around 67 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Today: Breezy. Mostly sunny with isolated showers. Highs around 77 near the shore to 67 to 76 near 3000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows around 63 near the shore to 51 to 58 near 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Breezy. Partly sunny with isolated showers. Highs around 77 near the shore to 68 to 76 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Kohala

Today: Breezy. Mostly sunny with isolated showers. Highs around 77 near the shore to 67 to 76 near 3000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows around 63 near the shore to 51 to 58 near 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Breezy. Partly sunny with isolated showers. Highs around 77 near the shore to 68 to 76 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

South Big Island

Today: Mostly sunny. Highs around 80 near the shore to around 68 near 5000 feet. Northeast winds up to 10 mph shifting to the southeast in the afternoon.

Tonight: Partly cloudy. Lows around 67 near the shore to around 49 near 5000 feet. Northeast winds around 10 mph.

Wednesday: Mostly sunny. Breezy. Highs around 80 near the shore to around 68 near 5000 feet. East winds 10 to 20 mph.

Puna

Today: Mostly sunny with isolated showers. Highs around 78 near the shore to 63 to 69 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 67 near the shore to around 52 at 4000 feet. Northwest winds around 10 mph. Chance of rain 50 percent.

Wednesday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 79 near the shore to around 66 at 4000 feet. Northwest winds around 10 mph shifting to the northeast in the afternoon. Chance of rain 40 percent.

Waikoloa

Today: Sunny and breezy. Isolated showers in the afternoon. Highs around 80 near the shore to around 67 above 4000 feet. East winds up to 20 mph shifting to the north in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Breezy. Lows around 68 near the shore to 46 to 53 above 4000 feet. Southeast winds 10 to 20 mph.

Wednesday: Mostly sunny. Highs 78 to 83 near the shore to around 67 above 4000 feet. Southeast winds 10 to 15 mph shifting to the north in the afternoon.

Detailed Forecast

Synopsis

A stable airmass will prevail through the week, with showers affecting mainly mountain and windward areas. Breezy trade winds will continue through Wednesday, before turning from the southeast Thursday and into the weekend. Showers may increase late Sunday and into next week.

Discussion

Satellite and radar show very limited clouds and showers over Kauai and the Big Island, so have toned down the PoPs and associated fields for those areas this morning. Otherwise forecast remains largely untouched.
A dry and stable airmass remains over the islands and will limit rainfall totals for another couple of days. Breezy trade winds will focus any clouds and showers to the typical windward and mountain areas into Wednesday. This overnight soundings showed nearly the same precipitable water (PW) values as 12 hours ago (.69 at Lihue and .9 at Hilo), both below normal for January. Satellite derived PW shows the dry airmass over and immediately upstream of the islands, and models all show the dry airmass sticking around much of the week.
High pressure to the far northeast, a ridge north of the islands, and a low to the southeast will maintain a breezy trade wind pattern over the region into Wednesday. A front to the northwest will factor in to the local weather during the second half of the week. The southern end of the front is already starting to stall out and weaken, and is not expected to hold together as it reaches the islands. However as front does approach the islands, it will push the ridge closer to the islands, turning our winds to a more southeasterly direction. Another front approaching the islands from the northwest Friday and on into the weekend will help to maintain that southeasterly flow. The southern end of the this front is also expected to weaken as it approaches the islands.
Another front approaching from the northwest late in the weekend currently has a better shot of hanging in there and reaching the western end of the state early next week. This front would more significantly boost moisture over the islands, resulting in an uptick in rainfall totals. Not expecting anything of concern at this time, but definitely higher rainfall totals that what is expected over the next several days.

Aviation

Shallow, shower-bearing stratocu has expanded in coverage early this morning resulting in an increase of windward showers for Oahu through Maui. VFR is still expected to prevail, but occasional MVFR will be possible within this activity. Showers will diminish in coverage by late this morning, but the central islands will still observe increased windward cloud cover compared to yesterday. Locally breezy trades remain supportive of lee turbulence for Molokai through Big Island.
AIRMET Tango for lee turbulence below 8kft for Molokai through Big Island and has been cancelled for Oahu.

Marine

Moderate to locally strong trades will continue through Wednesday, with winds holding at or near advisory levels in the typically windy waters around Maui and the Big Island. A Small Craft Advisory (SCA) remains in effect for most of the typically windy waters around Maui and the Big Island through 6 PM this evening. The SCA has been cancelled for all other waters as seas have dropped below 10 feet.
Winds are expected to ease Thursday and Friday as a cold front approaches and stalls out northwest of the island chain. This should bring a period of light and variable winds to the western islands, while light to moderate trades hold over the eastern end of the state. A brief return of moderate to fresh trades is expected across most of the marine area Friday night and Saturday, with moderate to fresh southeasterly winds potentially developing in advance of the next cold front on Sunday.
Buoy observations indicate that the current northwest swell has lowered just below advisory levels, and as a result, the High Surf Advisory has been cancelled. A new re-inforcing northwest swell will arrive Wednesday and may push surf heights back up close to low end advisory levels along exposed north and west facing shores through early Thursday. This swell will lower later Thursday, with surf expected to be well below seasonal levels on Friday. The next in a series of northwest swells should arrive Friday night and may once again push surf up into the advisory range along north and west facing shores late Saturday through early Sunday with a downward trend then expected through early next week.
East shore surf will remain a bit elevated today as the current small east swell slowly fades. The downward trend will continue on Wednesday, with very small surf then expected for east facing shores Thursday through the weekend, with perhaps a slight boost early next week.
South shore surf will remain very small through Thursday, with a small boost possible Friday through the weekend as a small south swell arrives.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST this evening for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov